A few preparatory steps need to be performed on every CAD model before moving it into the CAM environment. Throughout this chapter, we are going to work with one of the models that were given in the exercise problems. For a change, all the units are followed in millimeters in this model and manufacturing of the component.
Before getting started, it would be helpful if you can get into a CAM Express Role. To do this, go to the Roles menu on the Resource Bar and click on the INDUSTRY SPECIFIC tab. A drop-down menu will pop up in which the CAM Express role can be seen as shown in the figure.
9.1.1 Creation of a Blank
After completing the modeling, you should decide upon the raw material shape and size that needs to be loaded on the machine for the actual machining. This data has to be input in NX5.
This can be achieved in two ways. The first method is by creating or importing the model of the raw material as a separate solid in the same file and assigning that solid as the Blank. The second method is by letting the software decide the extreme dimensions of the designed part and some offset values if wanted. The later method allows a quick way of assigning the raw size details but it can only be used for prismatic shapes.
¾ Open the file ‘Die_cavity.prt’ of the exercise problem in Chapter 6
¾ Click on START → MODELING
¾ Create a block with the following dimensions and positioning.
Length = 150 mm Width = 100 mm Height = 80 mm
Using the Point Constructor icon located on the toolbar as shown:
Position the block at the point (-75, -50, -80).
This block encloses the entire design part so we will change the display properties of the block.
¾ Click on the EDIT OBJECT DIPLAY icon on the toolbar as shown.
Two features, labeled as BLOCK, show up in the QUICKPICK menu, one for the design part and one for the block.
¾ Move your mouse on the labels to see which one represents the block
¾ Select the block you created
¾ Click OK
¾ When the window pops up, change the display color and change the Translucency to 50
¾ Then click OK
Hide the block you just created by right clicking on the block in the Part Navigator. This will make the raw block disappear from the environment. Whenever you want to view or work on this solid, reverse the blanks. This is done by pressing <Ctrl> + <Shift> + B.
9.1.2 Setting Machining Environment
Now we are set to get into the Manufacturing module.
¾ Select START → MANUFACTURING
A window will pop up asking for the Machining Environment Setup. There are many different customized CAM sessions available for different machining operations. Here, we are only interested in the Milling operation.
¾ For CAM Session Configuration, select cam_general and for CAM Setup, select mill_contour. This window pops up when you start the Manufacturing Application
¾ Click INITIALIZE
9.1.3 Operation Navigator
As soon as you get into the Manufacturing environment, you will notice many changes in the main screen such as new icons that are displayed.
¾ Click on the OPERATION NAVIGATOR tab on the right on the RESOURCE BAR
The Operation Navigator gives information about the programs created and corresponding information about the cutters, methods, and strategies.
The list of programs can be viewed in different categorical lists. There are four ways of viewing the list of programs in the Operation Navigator. The four views are Program Order view, Machine Tool view, Geometry view and Machining Method view. If you want to view the list of programs under different cutter tools, you can do so by clicking the particular icon in the top toolbar.
9.1.4 Machine Coordinate System (MCS)
¾ Click on the Geometry View icon in the toolbar to initiate setup for programming
¾ On the Operation Navigator window, double-click on MCS_MILL A pop-up window will allow you to set the MCS however,
you want. NX5 by default takes the original WCS as the MCS.
¾ Click on the button shown. This will highlight the default WCS of the part and assign it as the MCS
¾ Click OK to select it as the MCS
¾ Click OK when you are done orienting and positioning the MCS
9.1.5 Geometry Definition
¾ Double-click on WORKPIECE in the Operation Navigator. If you don’t see it, click on the plus sign next to MCS_MILL
The pop up window MILL_GEOM appears. This is where you can assign the part geometry, blank geometry, and check geometry if any.
¾ Click on the Part icon
¾ Select the design part and click OK
Now we have to select the Blank Geometry.
¾ Click the Blank icon
This will open the Blank Geometry Window. As mentioned earlier there are many ways to assign the blank.
You can use a solid geometry as the Blank or can allow the software to assign a prismatic block with desired offsets in the X, Y, and Z directions. As we have already created a Rectangular Solid Geometry, we can use that as the Blank geometry. Remember that our block is hidden.
¾ Retrieve the block by pressing <Ctrl> + <Shift> + B
¾ In the Blank Geometry window, make sure the Geometry radio button is selected
¾ Select the block and click OK
¾ Bring the part geometry back by pressing <Ctrl> +
<Shift> + B once again
¾ Click OK on the MILL_GEOM dialog box
Now we are finished assigning the Part and Blank geometries. Sometimes it may be required to assign Check geometry. This option is more useful for shapes that are more complex or 5-Axes Milling operations where the Tool cutters have a higher chance of dashing with the fixtures. In our case, it is not very important to assign a Check Geometry.
9.2 CREATING OPERATION AND PARAMETER SETTING